sorry not a merc, just found these, you really have to give a lot of credit to the people between ww1 and ww2, the crazy ideas they came up with that werent tried again, or in thi s case just not for 70 years....
and a few more..... and the blue car above has a u16 with 2 superchargers
the giant green engine was a tank engine called the chrysler multibank, it was a massive 30 cylinder engine combining 5 inline 6 engines for better reliablity....